chametz

Foods not eaten during Passover. Chametz typically includes leavened bread or any food that contains wheat, rye, barley, oats, or spelt, unless production has been supervised to ensure that it has not leavened.

matzah

Unleavened bread eaten during the seder that symbolizes the hurried departure of the Israelites from Egypt. Eating matzah is obligatory only at the seder. During the rest of Pesach, one may abstain from matzah as long as all chametz is avoided; plural: matzot